title: Magnetization exchange with water and T1 relaxation of the downfield resonances in human brain spectra at 3.0 T.
abstract: The use of water suppression for in vivo proton MR spectroscopy diminishes the signal intensities from resonances that undergo magnetization exchange with water, particularly those downfield of water. To investigate these exchangeable resonances, an inversion transfer experiment was performed using the metabolite cycling technique for non-water-suppressed MR spectroscopy from a large brain voxel in 11 healthy volunteers at 3.0 T. The exchange rates of the most prominent peaks downfield of water were found to range from 0.5 to 8.9 s(-1), while the T(1) relaxation times in absence of exchange were found to range from 175 to 525 ms. These findings may help toward the assignments of the downfield resonances and a better understanding of the sources of contrast in chemical exchange saturation transfer imaging.
authors.affiliation: Department of Clinical Research, University of Bern, Bern, Switzerland.
authors.forename: Erin L
authors.initials: EL
authors.lastname: MacMillan
authors.forename: Daniel G Q
authors.initials: DG
authors.lastname: Chong
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dreher
authors.forename: Anke
authors.initials: A
authors.lastname: Henning
authors.forename: Chris
authors.initials: C
authors.lastname: Boesch
authors.forename: Roland
authors.initials: R
authors.lastname: Kreis
mesh_terms: D000328:Adult; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011522:Protons
chemical_list: D011522:Protons